Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1887-12-31
DeWaY MILDEW.
IT'S PRESENCE IN SOME CALiFOR.
MA VINEYARDS.
An Easy Pest to Control-Remedies
Suggested by the National De-
partment CT Agriculture.

The following communication has been
received by the San Francisco Bulletin, and
will be of interest to vineyardists of the
State:
EDITOR BULLETIN: In the letter from
me recently published in the Bulletin.
made the statement that at was very
doubtful if downy mildew (Peronospora
Ulticotd) occurred within the limits of your
State" This statement was based upon
the fact that did not find any evidence of
the presence of the fungus in the districts
which | had been led to believe infected,
from reports of grape-growers. This let
ter has been the means of bringing into
public notice the communication made by
Dr. III. w. Hardness to the California
Academy of Sciences in June last, wherein
he records having found the downy mildew
in a vineyard near Sacramento in 1872. and
again in 1884 on the wild vine near Bart
lett Springs, Lake county, and at Russian
river, 1886.
While regretting the fact--the presence
of the downy mildew in California-which
so eminent an authority on fungi as DIR.
darkness has now placed beyond question,
feel that my recent letter was of some
value, inasmuch as it has now led the
doctor to speak where the public interested
may hear his voice.
In regard to remedies it has been clearly
demonstrated that the downy mildew NAV
be controlled with nearly the same ease as
the odium or powdery mildew. Every
grape-grower knows that applications of
the flowers of sulphur are sufficient to keep
the latter in check. Preparations con-
tanning sulphate of copper, when properly
applied, have been found to be equally
efficient in the case of the downy mildew.
only with the latter disease it must be re-
membered that the remedies can act only
as preuentireS. The eau celeste solution o,
the Bordeaux mixture, have given the
best results.
Eau Celeste, Blue Water (the "Auduy-
maud process ")-Dissolve one pound of
sulphate of copper in three or four gallons
OF warm water when completely dissolved
and the water has cooled, add one pint of
commercial ammonia then dilute to thirty
gallons. The concentrated liquid should
be kept IN key or some wooden vessel
and diluted when required for use. Apply
the same as in the case of simple solutions.
The effects obtained by this preparation
have been equal to those resulting from the
use OF the copper mixture of Gironde. and
It's adherence to the foliage is even greater.
Copper Mixture of Gironde, Bordeaux
Mixture-Dissolve ten pounds of sulphate
OF copper IN twenty-five gallons of water ::
in another vessel slake twenty pounds of
lime in six gallons of water. When the
latter mixture has cooled it is sIowlv poured
INTO the copper solution, care being taken to
mix the fluids thoroughly by constant
stirring. 1t is well to have this compound
prepared some days before it is required
for use. 1t should be well stirred before
applying. Some have reduced the ingredi-
ents to two pounds of sulphate of copper
and two pounds of lime to twenty-five
gallons of water and have obtained good
results.
Well-made pumps with specially con-
structed nozzles are required for the appl-
cation of this compound, unless we resort
to the tedious and wasteful method of
using brooms or whisps made of slender
twigs, which are dipped into the compound
and then switched right and left so as to
spray the foliage, as directed in our circu-
lar of last season. The Vermorel appar-
atus, including reservoir, pump and spray
'5 NSiN, 10 well dudPteu IOr vineyard
use and is specially constructed for apply
ing the various liquid preparations CON
tanning sulphate of copper.
The results of many chemical analyses of
the fruit and parts of vines treated with
the copper compounds have clearly shown
that there is no danger to health attending
their application. The only precaution
advised is not to apply them near within
fifteen days of the vintage.
In their employment the fact must be
kept in mind that their action is only pre-
ventive, therefore their application should
be made early in the season, as soon as the
first leaves are fully formed Subsequent
applications act only in so far as they serve
to check the spread of the disease The
amount of the fluid compounds required to
treat an acre of vines will depend largely
upon the kind or pump and spraying nozzle
used to apply them, and upon the extent
of growth Of the vines themselves; the
amount may vary from twenty to thirty
five gallons at each application.
+. l.. SCRIBNER,
Chief of the Section of Vegetable Pathol-
Ogy, United States Department of Agri-
culture.
WASHINGTON, d. c., Dec 20, 1887.